The crystal state of a compound can be important when the compound is used for pharmaceutical purposes. Compared with an amorphous solid, the solid physical properties of a crystalline compound can change, which can affect its suitability for pharmaceutical use. For example, a particular crystalline compound can overcome the disadvantage of other solid forms of the compound that readily absorb moisture (high hygroscopicity). For an ionic drug substance, high hygroscopicity can diminish the drug product's stability profile by a host of mechanisms, as the drug substance may have a propensity to absorb water. Water that is absorbed from the environment (packaging materials, exposure to air, or in the case of formulated products, from other materials), can lead to degradation products and/or impurities in a drug product or add to the cost of manufacturing the drug product with acceptably low levels of water.
There is a need for solid forms of (2S,5R)-2-(1,3,4-oxadiazol-2-yl)-7-oxo-1,6-diazabicyclo[3.2.1]octan-6-yl hydrogen sulfate for use in drug substance and drug product development.